> browse/registry

> posthog

Open-source product analytics with PostHog — event tracking, funnels, cohorts, session replay, feature flags, and experimentation. Self-host with Docker or use PostHog Cloud. Covers JavaScript SDK for frontend tracking, Python SDK for backend events, autocapture configuration, custom event taxonomies, and funnel/retention analysis. Use when tasks involve adding product analytics, understanding user behavior, debugging UX with session replay, or rolling out features with feature flags.

> fast-check

Find edge-case bugs with property-based testing using fast-check — generate thousands of random inputs automatically. Use when someone asks to "find edge cases", "fast-check", "property-based testing", "fuzz testing in TypeScript", "generate random test data", "QuickCheck for JavaScript", or "test with random inputs". Covers property definitions, arbitraries, shrinking, model-based testing, and integration with Vitest/Jest.

> tsup

Bundle TypeScript libraries with tsup — zero-config, powered by esbuild. Use when someone asks to "bundle a TypeScript library", "build npm package", "tsup", "publish TypeScript to npm", "build ESM and CJS", "bundle with esbuild", or "library bundling with zero config". Covers ESM/CJS dual output, declaration files, tree-shaking, and npm publishing.

> biome

You are an expert in Biome, the Rust-based toolchain that replaces ESLint and Prettier with a single, fast tool. You help developers configure linting, formatting, and import sorting for JavaScript, TypeScript, JSX, JSON, and CSS — achieving 100x faster execution than ESLint+Prettier with zero configuration, unified diagnostics, and IDE integration.

> blender-animation

Animate 3D objects and characters in Blender with Python. Use when the user wants to keyframe properties, create armatures and rigs, set up IK/FK chains, animate shape keys for facial animation, edit F-Curves, use the NLA editor to blend actions, add drivers for expression-based animation, or script any animation workflow in Blender.

> bun

Assists with using Bun as an all-in-one JavaScript/TypeScript runtime, package manager, bundler, and test runner. Use when building HTTP servers, managing packages, running tests, or migrating from Node.js. Trigger words: bun, bun serve, bun install, bun test, bun build, javascript runtime, bun runtime.

> security-best-practices

Perform language and framework specific security best-practice reviews and suggest improvements. Trigger only when the user explicitly requests security best practices guidance, a security review/report, or secure-by-default coding help. Trigger only for supported languages (python, javascript/typescript, go). Do not trigger for general code review, debugging, or non-security tasks.

> pdfkit

Generate PDF documents programmatically with PDFKit — add text, images, vector graphics, tables, headers/footers, and custom fonts. Use when tasks involve creating invoices, reports, certificates, or any structured PDF output from application data in Node.js.

> capacitor

Turn web apps into native mobile apps with Capacitor — access native device APIs from JavaScript. Use when someone asks to "convert my website to a mobile app", "Capacitor", "web to native app", "access camera from JavaScript", "deploy web app to App Store", "hybrid mobile app", or "Ionic Capacitor". Covers native API access, plugin system, web-to-native bridge, and app store deployment.

> cassandra

Apache Cassandra is a distributed NoSQL database designed for high availability and linear scalability. Learn CQL (Cassandra Query Language), data modeling with partition keys, replication strategies, and integration with Node.js using the DataStax driver.

> changesets

Assists with managing versioning and changelogs in JavaScript/TypeScript monorepos using Changesets. Use when automating semantic versioning, generating changelogs from PRs, coordinating multi-package releases, or publishing to npm. Trigger words: changesets, versioning, changelog, npm publish, monorepo release, semver.

> clerk-auth

Add authentication to web apps with Clerk — social login, email/password, magic links, organizations, RBAC, session management, webhooks, and multi-framework support. Use when tasks involve user authentication, team/org management, role-based access control, or integrating auth into Next.js, React, Remix, or Express applications.

> azure-servicebus-ts

Build messaging applications using Azure Service Bus SDK for JavaScript (@azure/service-bus). Use when implementing queues, topics/subscriptions, message sessions, dead-letter handling, or enterprise messaging patterns.

> azure-storage-blob-ts

Azure Blob Storage JavaScript/TypeScript SDK (@azure/storage-blob) for blob operations. Use for uploading, downloading, listing, and managing blobs and containers. Supports block blobs, append blobs, page blobs, SAS tokens, and streaming. Triggers: "blob storage", "@azure/storage-blob", "BlobServiceClient", "ContainerClient", "upload blob", "download blob", "SAS token", "block blob".

> azure-web-pubsub-ts

Build real-time messaging applications using Azure Web PubSub SDKs for JavaScript (@azure/web-pubsub, @azure/web-pubsub-client). Use when implementing WebSocket-based real-time features, pub/sub messaging, group chat, or live notifications.

> wiki-ado-convert

Converts VitePress/GFM wiki markdown to Azure DevOps Wiki-compatible format. Generates a Node.js build script that transforms Mermaid syntax, strips front matter, fixes links, and outputs ADO-compatible copies to dist/ado-wiki/.

> copilot-sdk

Build applications powered by GitHub Copilot using the Copilot SDK. Use when creating programmatic integrations with Copilot across Node.js/TypeScript, Python, Go, or .NET. Covers session management, custom tools, streaming, hooks, MCP servers, BYOK providers, session persistence, custom agents, skills, and deployment patterns. Requires GitHub Copilot CLI installed and a GitHub Copilot subscription (unless using BYOK).

> agentic-actions-auditor

Audits GitHub Actions workflows for security vulnerabilities in AI agent integrations including Claude Code Action, Gemini CLI, OpenAI Codex, and GitHub AI Inference. Detects attack vectors where attacker-controlled input reaches AI agents running in CI/CD pipelines, including env var intermediary patterns, direct expression injection, dangerous sandbox configurations, and wildcard user allowlists. Use when reviewing workflow files that invoke AI coding agents, auditing CI/CD pipeline security f

> apify-actorization

Convert existing projects into Apify Actors - serverless cloud programs. Actorize JavaScript/TypeScript (SDK with Actor.init/exit), Python (async context manager), or any language (CLI wrapper). Use when migrating code to Apify, wrapping CLI tools as Actors, or adding Actor SDK to existing projects.

> antfu

Anthony Fu's opinionated tooling and conventions for JavaScript/TypeScript projects. Use when setting up new projects, configuring ESLint/Prettier alternatives, monorepos, library publishing, or when the user mentions Anthony Fu's preferences.